Method and apparatus for sealing continuously moving sheet material



J y 1965 A. s. HUBIN 3,195,286

7 METHOD AND APPARATUS FOR SEALING CONTINUQUSLY MOVING SHEET MATERIALFiled Aug. 20, 1962 2 Sheets-Sheet 1 y 1965 A. s. HUBIN 3,195,286

METHOD AND APPARATUS FOR SEALING CONTINUOUSLY MOVING SHEET MATERIALFiled Aug. 20, 1962 v 2 Sheets-Sheet 2 T 4 2 Q 3 E O 1 I .2. TV 341 1" IW jail 4 w 17 is E f 62 /if I?" w W l 1' H I i 4' E 3 Y 30 l Ill "lllzi1 M H I a E 5 uiCl E O Hill-I v ..n i if WW .HH

United States Patent 3,195,286 METl-i fii) AND APPARATUS FQR SEALING(IGN- TENU=O ULY M'QVENG SHEET MATERHAL Anthony S. Harbin, Appleton,Wis, assignor to Kimheriy- (l'lark Corporation, Neenah, Wis, acorporation of Deiaware Filed Aug. 20, 1962, Ser. No. 217,924 6 Claims.(Cl. 53-39) This invention relates to improved methods and associatedapparatus for sealing fabric-like material, with particular reference tosanitary napkin tab ends.

An important object of the invention resides in the provision of animproved apparatus for the periodic heat sealing of wrapper portions ofa continuously moving elongate pad and wrapper assembly during thefabrication thereof on apparatus of the continuously operative type.

Another object is to provide improved apparatus for the periodic sealingof tab ends of sanitary napkins, as formed on continuously operativeproduction apparatus, which require sufficient bonding to fix theconfiguration thereof while in the form of a continuously moving pad andwrapper assembly prior to the severance of the pad bridging wrapperportions to form individual sanitary napkins.

Another object is to provide an improved and simplified wrapper sealingdevice adapted to be constructed at minimum cost while insuring maximumdependability of operation.

Other objects and advantages will become apparent to persons skilled inthe art, as will various adaptations and modifications of the conceptsas defined in the appended claims.

In the drawings, in which like parts are identified by the samereference numerals,

FIG. 1 shows in side elevation a portion of sanitary napkin productionapparatus incorporating the invention.

FIG. 2 shows in side elevation a portion of the apparatus of FIG. 1.

FIG. 3 is a fragmentary end elevation taken along line 3-3 of FIG. 2.

The invention has broad utility in respect to the mass production ofsuch light weight articles as bandages and sanitary napkins which duringfabrication thereof are enclosed in light weight wrapper material whichbridges spaced pads forming a continuously moving assembly which isthereafter severed into individual units. The invention is particularlyadapted for use with tab end forming equipment described and illustratedin appli- I cants concurrently filed co-pending' application, Serial No.217,923 filed August 20, 1962. A sealing unit involving the conceptsherein taught may be placed immediately adjacent a unit which convertspad bridging portions of wrapper into a desired tab end configuration.

As shown in FIG. 1, an assembly of wrapper enclosed pads with padbridging wrapper portions assuming a generally X-configuration in plan,or some other desired configuration, is fed in the direction of arrow Ainto a scaling unit generically designated 18. The preformed elongateassembly 10 comprising spaced pads 17 and an elongate enclosing Wrapper19 continuously moves downstream (to the left as shown). Assembly 10 ismaintained taut by continuously applied forward pull imparted by a pairof conveyor belts 12, 14 positioned downsteam of sealing unit 18frictionally to engage and continuously to draw the pad assembly. Toinsure that the pad assembly is fed to the sealing unit with pads 17horizontally disposed, a channel-like inlet device 16 is positionedadjacent the sealing unit. Unit 18 finds its support on a suitableframework 21 which also provides support for associated components.

Patented July 20, 1$fi5 Device 18 includes a pair of heat sealing shoes24, 26 synchronously operative in respect to the downstream movement ofthe pad and wrapper assembly between the spaced apart position. shown inFIG. 1 and a closed or wrapper engaging position shown in FIG. 2.

Heated shoes 24, 26 effect inter-pad wrapper sealing upon movement fromthe open position of FIG. 1 to the closed position, FIG. 2. Followingclosure, shoes 24, 26 are drawn downstream through a limited path by theengaged pad and wrapper assembly. The extent of downstream shoe movementis illustrated in FIG. 2 by the dotted line position which-may be threeor four inches downstream of the initial heavy line position showntherein. Shoes 24, 26 are dimensioned substantially to bridge theinter-pad spacing with the ends thereof engaging the pad ends. Uponcompletion of the movement from the heavy to the dotted line position ofFIG. 2 the shoes are rapidly withdrawn, by mechanism later described, tothe open upstream position of FIG. 1 in readiness for the subsequentcycle of operation. While the broad employment of sealing shoesoperative from an open to a closed position and adapted for engagmentwith moving articles to be sealed is known, the present invention isdirected to the employment of concepts permitting a very simplifiedconstruction with attendant low costs.

As illustated in FIGS. 1 and 2, the various components of the sealingunit are supported by a generally rectangular framework 23 fixed to themachine frame 21 with similar half portions thereof extending above andbelow the path of article travel. Sealing shoes 24, 26 are resilientlymounted by means of pairs of flexible flat springs 28, 30. Each pair ofshoes 2d, 26 is actuated through associated paired mounting springs 28,349 by a cam actuated control mechanism which includes two upper pairsof axially spaced crank discs 36, 38 and two pairs of lower axiallyspaced crank discs 46, 59. Each pair of crank discs is suitablyjournaled on shafts as shown at 4-0, 42, and upper paired discs 36, 38are driven for simultaneous rotation in a direction opposite to thelower paired discs 46, 50.

To effect synchonism between disc rotation and movement of articlesthrough the unit, a cam 56, and conveyor belt units 12, 14 which controlthe rate at which the pad and wrapper assembly is drawn in a downstreamdirection are driven from a common power source. A driving arm 54,pivoted at 55, carries a cam follower 58 maintained biased against cam56 by tension spring 6@ for the transmission of oscillatory movementthrough connecting rod 52 to one of the paired discs 46. Link 43interlocks discs 46, f r synchronized power transmission therebetweenthrough the relatively small arc of rotation required for the properactuation of paired shoes 24, 26 through the associated paired springs28, 30. The lower paired discs 46, 5% connected by rod 44 to one of theupper paired discs 38, provide for the synchonized driving of the twoupper paired discs 38, 36 which are interconnected by a link 31. Thus itwill be seen that rotation of cam results in the synchronized rotationof the two lower sets of paired discs, for example, in a clockwisedirection, and in the simultaneous synchronized counterclockwiserotation of the upper disc pairs 38, 36.

Upper and lower pairs of crank discs thus provide synchronized controlof upper and lower shoes 24, 2 5, respectively, through the flexibleleaf springs. The crank discs of each pair, such as pair 38 shown inFIG. 3, are interconnected by an eccentrically positioned rod 34extending parallel to the axis of shaft 42. Rod 34 and a like rod 32,FIG. 2, are interconnected by bar 31, thus connecting crank discs 36, 38for rotation as previously described. Link 31 has mounted thereto by asuitable amass-e bracket, as shown at 33, a flexible leaf spring 28, thelower end of which is attached by a bracket 35 to one end of shoe 24. ina like manner lower pairs of crank discs 46, 50 are interconnected bysimilar rods and brackets associated with the lower pair of mountingsprings 39 for the flexible positioning of lower sealing shoe 26. Thetwo upper leaf springsfid are thus supported and actuated by crank discs33, 36, whereas the two lower leaf springs 30 are supported and actuatedby lower pairs of crank discs 50, 56. The crank disc connecting rods arepositioned radially of the crank disc axes sufiiciently to insuresynchronized movement of shoes 24, as between the open position shown inFIG. 1 and the closed position shown in FIG. 2.

FIG. 1 illustrates shoes 24, 26 in a fully opened position just'prior tobeing closed by cam 55, it being noted that spaced pads 17 are in aposition to place the bridging Wrapper portion in substantial registrywith the areas of shoe engagement therewith. The action of cam 56.

is quite rapid and as follower 58 rides upwardly onto the minorcylindrical cam surface the above described crank disc movement effectsrapid shoe closure. As shown in FIG. 2, opposite ends of each shoe arebeveled and upon shoe closure define V-shaped channels 62, 64 whichinsure snug engagement with corresponding ends of the pads 17. Thebridging portion of the wrapper is thus securely clamped between theshoes 24, 26 which are maintained suitably heated 'by elements partiallyshown at 27 and connected through lead line fixtures 29 to a suitablesource of electricity. Positive closure of shoes 24-, 26 effects lockingengagement with the pad and wrapperassembly, hence continued travel ofthe assembly in the downstream arrow direction results in acorresponding movement of'the shoe assembly through'a suflicient linearpath to insure proper bonding of the wrapper. The time of travel neednot be great and may, for example, involve a three inch path of travelat the end of which the shoes open and return by snap back to the FIG. 1position. I

The actuating mechanism maintains shoes 24, 26 in a closed position asthe shoes arepulled downstream by the pad and wrapper assembly, duringwhich movement paired mounting springs 28, 30 undergo substantialdeflection, as shown in the dotted'line position, FIG. 2. When in thedownstream position, the shoes are subjected to maximum spring urgetoward the full line position. As the closed shoes move downstream tothe.

dotted line position of FIG. 2, cam follower 58 concurrently rides tothe outermost cam portion with resultant rapid retraction of the shoesupporting springs to an open shoe position. Resultant shoedisengagement from the pad assembly permits the tensioned shoesupporting springs to snap back from the dotted line position of FIG. 2to the full line position of FIG. 1, with corresponding repositioning ofshoes 24, 26 in readiness for a subsequent cycle.

It will thus be appreciated that the invention provides an extremelysimple and inexpensive apparatus for sealing pad bridging wrapperportions of a moving pad and wrapper assembly. In addition to lowinitial cost, the

apparatus is relatively free from maintenance costs due to itssimplicity. Apparatus employing the invention has proved particularlyeifective for use immediately downstream of applicants sanitary napkintab end forming equipment as described and claimed in co-pendingapplication, Serial No. 217,923, filed August 20, 1962. The inventionpermits replacement of the relatively complex mechanisms heretoforeconstructed within close machine i tolerances to effect satisfactorysealing of continuously moving materials by a comparatively simple buthighly dependable mechanism, due largely to applicants utilization ofthe inherent benefits of leaf springs asdescribed above. In addition,variations in the speed at which the pad and wrapper assembly moves donot affect the operation of the sealing shoes, since their flexiblespring mountings allow them to adjust to any variations in speed.

In the claims:

1.1m a device for sealing continuously moving sheet material, means forconveying said material through a certain path, a pair of sealingmembers spaced on opposite sides of said path, and means for mountingsaid sealing members and synchronized with said conveying means formoving said members in a direction substantiallyat right angles to saidpath toward and into contact with the sheet material, said mountingmeans including spring means arranged to yield in such manner as toallow said sealing'members tomove in the direction of said path so thatthe sheet material pulls the sealing members along the path against theaction of the spring means while the sealing members remain in contactwith the sheet material.

'2. In a device for sealing continuously moving sheet material of a typewhich maybe sealed by the application of heat, means for conveying thesheet material at a constant speed through a linear path, a pair ofsealing members spaced on opposite sides of said path, means for heatingsaid sealing members, and means for mounting said sealing members andsynchronized with said conveying means for moving said members in adirection substantially at right angles to said path toward and intocontact with the sheet material, said mounting means including springmeans arranged to yield in such manner as to allow said sealing membersto move in the direction of said path sotliat the sheet material pullsthe sealing members along the path against the action of the springmeans While the sealing members remain in contact with the sheetmaterial to seal the latter.

3. In a devicefor sealing continuously moving sheet material, means forconveying the. material through a linear path, a pair of sealing membersspaced on opposite sides of said path, means for'mounting saidsealing'me'mbers and arranged to move the sealing members substantiallyat right angles to said path toward and into contact with the sheetmaterial, said mounting means including spring means arranged to yieldin such manner as to allow said sealing members to move in the'directionof said path so that the sheet material pulls the sealing members'alongthe path against the action of the spring means while the'seali'ngmembers remain in contact with the sheet material, and means forsynchronizing the movement of said mounting means along with'saidmaterial conveying means so that the sealing members are withdrawn fromthe sheet material after moving with the sheet material for apredetermined distance along said path.

4. In a device for sealing continuously moving sheet material, means forconveying the material at a constant speed through a linear path, a pairof elongated sealing members spaced on opposite sides of said path,means for mounting said sealing members and including a leaf springconnected at one end of the spring to each end of each of the sealingmembers and extending approximately transversely of said path andincluding also movable sup ports for the other ends of said leafsprings, and means for moving said supports in a direction approximatelyat rightangles to said path so asto move the sealing members throughsaid leaf springs substantially at right angles to said path toward andinto contact with the sheet material, said leaf springs being soarranged to yield in such manner as to allow said sealing members tomove in the direction of said path so that the sheet material pulls thesealing members along the path'a gainst the flexing action of the leafsprings while the sealing members in contact with the sheet material.

5.. In a device .for sealing continuously moving sheet material, meansfor conveying the sheet material at a constant speed through a linearpath, a pair of elongated sealing members spaced on opposite sides ofsaid path,

means for mounting said sealing members and including a leaf springconnected at one end of the spring to each end of said sealing membersand an eccentric connected to the other end of each of said leafsprings, said eccentrics and leaf springs being so arranged that theelongated sealing members are moved in a direction substantially atright angles with said path into contact and out of contact with thesheet material as said eccentrics are rotated and the leaf springs beingarranged to yield to allow the sealing members to move in the directionof said path so that the sheet material pulls the sealing members alongthe path against the action of the leaf springs after the sealingmembers have been moved into contact with the sheet material, and meansfor rotating said eccentrics in synchronized relationship with respectto said material conveying means so that said elongated sealing membersare moved out of engagement with the sheet material after havingtraveled a predetermined distance with the sheet material.

6. The method of fabricating sanitary napkins comprising the steps ofcontinuously forming an assembly of spaced apart absorbent pads enclosedin an elongated wrapper material, continuously moving said assemblythrough a linear path while maintaining said Wrapper material taut withportions thereof bridging the space between said pads, moving a pair ofheated members from opposed spaced apart positions outside the path ofmovement of said assembly and in a direction substantially at rightangles to said path into contact With the assembly within said path andallowing the wrapper material to pull the members along with the wrappermaterial due to the engagement of the members with the Wrapper materialwhile the members effect flattening and sealing of the pad bridgingwrapper material intermediate said pads, and thereafter returning saidheated members to their original spaced apart positions outside saidpath of Wrapper movement.

References Cited by the Examiner UNITED STATES PATENTS 1,341,408 5/20Armstrong.

1,953,122 4/34 Munson et al.

2,893,187 7/59 Tebbutt 53l80 3,020,687 2/62 Joa 53--28 X FRANK E.BAILEY, Primary Examiner.

6. THE METHOD OF FABRICATING SANITARY NAPKINS COMPRISING THE STEPS OFCONTINUOUSLY FORMING AN ASSEMBLY OF SPACED APART ABSORBENT PADS ENCLOSEDIN AN ELONGATED WRAPPER MATERIAL, CONTINUOUSLY MOVING SAID ASSEMBLYTHROUGH A LINEAR PATH WHILE MAINTAINING SAID WRAPPER MATERIAL TAUT WITHPORTIONS THEREOF BRIDGING THE SPACE BETWEEN SAID PADS, MOVING A PAIR OFHEATED MEMBERS FROM OPPOSED SPACED APART POSITIONS OUTSIDE THE PATH OFMOVEMENT OF SAID ASSEMBLY AND IN A DIRECTION SUBSTANTIALLY AT RIGHTANGLES TO SAID PATH INTO CONTACT WITH THE ASSEMBLY WITHIN SAID PATH ANDALLOWING THE WRAPPER MATERIAL TO PULL THE MEMBERS ALONG WITH THE WRAPPERMATERIAL DUE TO THE ENGAGEMENT OF THE MEMBERS WITH THE WRAPPER